There was a wide range of economic, political and social reasons for Prohibition.
Organisations that promoted temperance such as the Anti-Saloon League (ASL) and the Women’s Christian Temperance Union (WCTU) campaigned hard for Prohibition.
Some religious groups, such as the Methodists and Baptists, joined the crusade.
This was because:
Businessmen, such as Henry Ford, supported Prohibition because they felt alcohol lessened the efficiency of their workers.
Brewers argued beer was healthy and spirits were harmful in the hope of deflecting criticism from themselves. Thus, there was not a united front by the liquor industry against Prohibition.
Most big liquor manufacturers were German, for example Budweiser, and it was seen as unpatriotic (disloyal to the USA) to consume it.
Many Americans disapproved of immigrants because of the prevalence of drinking in their communities, such as the Irish, German and eastern European areas. Anti-immigrant feeling was therefore linked to support for Prohibition.
Politicians, who often drank in private, supported Prohibition in public because they did not want to lose votes in elections.
Revenue from the relatively new tax on people’s incomes would make up for the loss of money from taxes on alcohol.